If Queen Underwood were an animal, she claims, she'd be a lion. "I didn't say 'lioness,'" she clarifies. "Because lions are kings of the jungle, and I'm going to be on top."

It's not an idle boast: At 28, Underwood may be America's best chance to medal in the Olympic Games' first-ever women's boxing competition. Extraordinarily quick and fluid, with machine-like focus on her opponent, she's aware that all eyes will be on her as her sport makes its highly anticipated debut in London—and she likes it that way. But despite her confidence, Underwood's road to the apex of boxing has been anything but easy.

Along with her sister, Hazzauna, 30, Queen endured years of physical and sexual abuse at the hands of her father. "He was a monster," she recalls of Azzad Underwood, who divorced his young wife and seized full custody of his daughters when they were toddlers, eventually moving them from Seattle to South Carolina. He began molesting Hazzauna when she was about 12, and Queen a couple of years later. Eventually, they confided in each other and reached out to their estranged mother, who took them in back in Seattle. Today, Queen speaks of her dad—who served years in prison for his crimes—matter-of-factly: "I forgive him, but I don't have a father."

Though the abuse ended, Queen was rudderless throughout high school. Despite being a gifted basketball player and track star, she never fully cultivated her athletic talent. Instead, after graduation, she sank into a depression. "I was hanging out on the party scene, and I didn't have any motivation," she recalls. When she was 19, a friend suggested she check out a small local boxing gym. Stepping into the corner ring, Queen felt something click. "Before, I was hiding a lot inside," she says, "but boxing gave me that voice, that confidence." Working out, she grew powerful, strong and—for the first time—hopeful for her future. "I saw boxing as a way to be great and have people look up to me," she says.

Queen began training zealously, working a hodgepodge of jobs—from graveyard shift security guard to journeyman sprinkler fitter—to pay the bills so she could spend her free time at the gym. She won her first national amateur boxing title in 2007; four more national championships followed. But Queen is adamant that her success is in spite of her past—and not because of it. "People want to mix the abuse with boxing," she says. "They say, 'Oh, Queen, that's why you're so badass in the ring!'" But Queen says she never thinks about pain or anger while boxing. "If you're mentally crowded like that, you can't have a good fight," she explains. She does admit that her troubled adolescence helped shape her love of the spotlight: "I want that attention that I've always craved, because I never got it as a kid."

In setting her sights on the gold medal, Queen hopes to inspire other survivors of childhood sexual abuse. Through her nascent Living Out the Dream Foundation, she plans to build a safe haven in Seattle where victims can find support. "I want to tell people, 'You can be successful at anything, no matter what happened in the past,'" she says. "'You don't have to blame yourself and live a life of failure or regret.'"